Moving grate device, method, and system for combustion

ABSTRACT

A solid fuel conveying system is presented. The system includes a low power agitating grate. The grate has a surface for burning solid fuel in a burner, such as a downdraft burner. The grate includes a rotating camshaft and a plurality of movable grate elements. Each movable grate element has a cam end and a slide end. A cam bore passes through the grate element cam end, and a slide bore passes through the grate element slide end. A slide pin passes through each movable grate slide bore. A plurality of cams are disposed along the rotating camshaft, with each cam disposed within a cam bore in one of the plurality of movable grates elements. A camshaft drive rotates the camshaft, thereby moving each grate element in accordance with the orientation of the cam passing through the corresponding cam bore of that grate element.

FIELD OF THE INVENTION

The present invention relates to fuel transport, and more particularly, is related to conveying solid fuel.

BACKGROUND

Solid fuel material is used in many applications. For example, combustible materials may be pelletized to simplify handling, transport and use. Examples of solid fuel material include coal, grains, wood chips and fuel pellets. Handling of solid fuel material for solid fuel burners provides unique challenges. The solid fuel should be continuously fed to the burner to maintain constant heat output and high efficiency. While liquid fuel or gas and propane burners may be regulated by forcing the fuel by pressure or by gravity, solid fuel feeders typically require mechanical means to transport fuel from a solid fuel hopper to the burner. Examples include augers and conveyor belts. These mechanical solid fuel feeders add costs to the burner, consume energy and require maintenance.

In addition to requiring a constant flow of fresh solid fuel, the spent fuel in a solid fuel burner should be removed. As used within this disclosure, the term “spent fuel” may refer to fuel that has been only partially combusted, or may refer to fuel that has been entirely combusted, for example in the form of fly ash, heavy ash, and/or clinkers. When many forms of solid fuel are burned, they produce particle emissions, known a fly ash, and leave spent fuel behind, known as heavy ash. The heavy ash can clog the airways required in the burner for efficient combustion. Therefore, the heavy ash should be systematically removed as fresh solid fuel is replenished. Heavy ash that is exposed to high heat may fuse, forming clinkers. Partially consumed fuel should not be removed until the combustible material in the solid fuel is fully spent. Mechanized conveyor methods may thus be monitored so the solid fuel is not fed through the burner too quickly, resulting in removing unspent fuel and producing additional waste material, or removing spent fuel too slowly, reducing burner efficiency.

In solid fuel combustion systems, “under air” refers to air that passes generally upward from beneath the fuel and up through the fuel, while “over air” refers to air that passes near or above the top of the fuel. Solid fuel is typically burned using a combination of under air and over air. Adjusting the amount of air, both over air and under air, can achieve higher or lower firing rates with the same size grate. There are both maximum and minimum limitations to the amount of air that can be introduced to a particular sized grate.

The heavy ash should be cleared from the burner to make way for fresh solid fuel. A known method for removing ash from a burner is to agitate the burning surface, or grate, so that the spent ash drops away through openings in the grate. However, such agitating grates have heretofore been excessively power consuming, complex, and expensive, making them impractical for some applications, for example, domestic or other low cost installations. Therefore a need exists for a simple, low power agitating grate.

SUMMARY

Embodiments of the present invention provide a moving grate device, method and system for combustion. Briefly described in architecture, a first aspect of the present invention is directed to an agitating grate, with a movable grate element. The movable grate element includes a solid fuel supporting surface, a bottom surface disposed substantially opposite the solid fuel supporting surface, a first side, a second side opposite the first side, a cam end, a slide end opposite the cam end, a cam bore disposed substantially at the cam end, the cam bore passing through the movable grate element between the first side and the second side. A first rotating camshaft is disposed through the cam bore. A first cam is disposed upon the first rotating camshaft within the cam bore. A camshaft drive is configured to rotate the first rotating camshaft.

Briefly described, a second aspect of the invention is directed to a method for agitating a burner grate, including the steps of providing a camshaft, providing a movable grate element having a cam end, a slide end, a cam bore disposed substantially at the cam end, and a slide bore disposed substantially at the slide end, providing a cam disposed along the rotating camshaft, the cam disposed within the cam bore in the movable grate element, and rotating the camshaft with a camshaft drive.

A third aspect, briefly described, is directed to a solid fuel transport and system. The system includes a solid fuel feeder having a chute configured to accommodate a solid fuel pile having a solid fuel surface, and a conveyer configured to receive solid fuel from the solid fuel feeder and convey the solid fuel away from the solid fuel feeder and convey the solid fuel to a destination.

Other systems, methods and features of the present invention will be or become apparent to one having ordinary skill in the art upon examining the following drawings and detailed description. It is intended that all such additional systems, methods, and features be included in this description, be within the scope of the present invention and protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principals of the invention.

FIG. 1 is a schematic diagram of a low power moving grate incorporated into a solid fuel combustion system.

FIG. 2A is a schematic diagram of an embodiment of an agitating grate.

FIGS. 2B and 2C are schematic diagrams of isolated elements from the agitating grate.

FIG. 3 is a detail of an agitating grate.

FIG. 4 is a diagram of a first solid fuel feeding system embodiment.

FIG. 5 is a diagram of a second solid fuel feeding system embodiment.

FIG. 6 is a flow chart of an embodiment of a method for conveying solid fuel.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.

Exemplary embodiments of a low power agitating burner grate are presented. In one exemplary embodiment, solid fuel may be conveyed from a hopper to the surface of an agitating grate, where combustion of the solid fuel occurs. The burner may be incorporate an updraft burner, where flames are drawn upward from the burner grate, or a downdraft burner, where flames are drawn downward through the bottom of the burner grate, for example, by an impelled air flow. When solid fuel is burned on the grate, the ash is removed. Fuel and ash from consumed fuel may be further conveyed by the movement of the low power movable grate. One or more cams deployed on a camshaft positioned through apertures in grate elements may cause the grate elements to move and convey fuel in a desired direction, and may similarly break up ash to facilitate removal.

Low Power Agitating Grate

FIG. 1 shows a schematic diagram of a first embodiment of a low power moving grate 500 incorporated into a solid fuel combustion system, or burner 100. The solid fuel combustion system 100 includes the grate 500, a fire chute 120, a firebox 130, and a motor 150. Solid fuel may burn upon the grate 500 while the grate allows flow through air ventilation for combustion. Solid fuel, for example, coal or wood pellets, is conveyed to the grate 500 surface through the fire chute 120 and burns on the surface of the burner grate 500 substantially within the firebox 130. Heavy ash from spent fuel may accumulate upon the surface of the burner grate 500. Accumulation of spent fuel may block the airflow in the burner required to burn the fuel, and may physically inhibit fresh fuel from reaching the burner via the fire chute 120. Spent fuel ash may be conveyed from a burn area of burner grate to an ash collection area, for example at the end of the grate 500 beyond the firebox 130.

FIG. 2A shows the first embodiment of the low power agitating grate 500 substantially as assembled with the firebox 130 (FIG. 1) removed for clarity. The grate 500 of the first embodiment has fixed grate elements 510, and a plurality of moving grate elements 520. The moving grate elements 520 alternate between fixed grate elements 510. The grate elements 510,520 have a flame side surface that supports the solid fuel while the solid fuel is combusting, and a bottom side, oriented substantially opposite the flame side. The moving grate elements 520, and/or the fixed grate elements 510 may have one or more air passages 550 cut into them, extending through the flame side surface to, for example, the bottom side. In alternative embodiments the air passages may extend from the flame side to one or both ends of the grate elements 510, 520. The air passages 550 may provide a conduit for air to be drawn through the grate elements 510, 520 to the burning solid fuel. Combustion air passing through the air passages 550 in the grate elements 510, 520 may act to cool the moving and stationary elements 510, 520. While the air passages 550 are generally depicted as straight in the drawings, air passages 550 may instead take an irregular path, for example, to aid in cooling the grate elements 510, 520.

While air passages 550 may serve to provide an outlet for hard ash to fall through the grate elements 510, 520 after the solid fuel is spent, it may be preferable that the ash be conveyed to an ash collection area at the end of the grate 500. It should be noted that while the spent fuel is generally referred to herein as ash, persons having ordinary skill in the art will recognize the spent fuel may take on other forms, such as fused ash or melted ash (clinker), and/or unspent fuel.

The grate elements 510, 520 may be supported by one or more substantially horizontal support rods 526, which may be held in place with a securing mechanism, for example, a retaining spring 527. For example, the retaining springs 527 may be any type of spring or flexible material to maintain a light pressure against the two outer stationary elements 510 to ensure all the elements 510, 520 remain in close proximity with each other. The retaining springs 527 allow for expansion and contraction as the elements 510, 520 heat and cool all the while remaining juxtaposed.

The support rods 526 may pass through a grate aperture 525 in the fixed grate element 510, and may similarly pass through a slide aperture 560 (FIG. 2B) in a movable grate element 520, or a movable grate element support rod aperture 527 (FIG. 2B). The support rod holds the fixed grate elements 510 in place, while allowing limited motion of the movable grate elements 520. The inner diameter of grate aperture 525 is substantially equal to the outer diameter of the support rod 526, so that the support rod may support a fixed grate element 510 with minimal movement in a plane substantially orthogonal to the grate aperture 525. In contrast, turning to FIG. 2B, the slide aperture 560 and movable grate element support rod aperture 527 may be substantially larger than the outer diameter of a support rod, allowing limited movement in the plane orthogonal to the slide aperture 560 and movable grate element support rod aperture 527.

While the first embodiment of the low power agitating grate 500 has fixed grate elements 510 held in place with a support rod passing through the fixed grate elements 510, there is no objection to other embodiments having different means for holding fixed grate elements 510 in place, for example, a clamp or bracket at the end of the fixed grate element 510, or other mechanisms, such as pins, screws, or bolts. In such embodiments, there may be no need for a support rod, so the support rod aperture 527 may be omitted. The slide aperture 560, depicted in FIG. 2B as a diagonal slot, may be a slot having other orientations, or may be other shapes, as appropriate to produce the desired movement of the top surface of the movable grate elements 520.

The slide aperture 560 may be configured be at a variety of angles with respect to the surface of the element 520 or parallel with the surface of the movable element 520 to give the desired effect. As shown in FIG. 2B, the slide aperture 560 may have an upward angle to move the movable element 520 in an upward direction as it moves away from the camshaft assembly 590 (FIG. 2A) due to the motion of cam lobes 535 (FIG. 2C) on the camshaft 530 (FIG. 2C). Of course, a variety of different common mechanisms familiar to persons having ordinary skill in the art may be used to guide motion of the movable element 520, for example, linkages, cams etc. It is desirable to rely on more than gravity to limit the upward movement range of the movable elements 520.

The top surface of the movable grate elements 520 may be formed to have shapes such as a sawtooth profile to aid in moving material forward. The top surface of the grate elements 510, 520 may be shaped differently in different portions of the grate to affect different results. For example, there may be a first surface contour for use in a fuel burning portion, and/or a second surface contour used in an ash conveying portion. Irregular shapes in the fuel burning portion may conduct more heat into the grate elements 510, 520, which may not be desirable. The entire grate 500 may be oriented in a substantially horizontal fashion, or angled somewhat in an upward or downward orientation, depending on the type of solid fuel being burned and the desired results.

The movable grate element 520 has a cam aperture 570. In the first embodiment of the agitating grate 500 (FIG. 2A) the cam aperture 570 is located toward an end of the movable grate element 520. However, there is no objection to placement of the cam aperture 570 in other locations along the length of the movable grate element 520. There is similarly no objection to embodiments having cam shafts in two or more locations along the grate 500, for example cam shafts passing through both ends of each grate element 510, 520.

FIG. 2C shows an isolated view of a cam shaft assembly 590. The cam shaft assembly is supported by two bearings 540 (FIG. 2A), and includes a cam shaft 530 passing through the bearings 540 (FIG. 2A) and a plurality of cams lobes 535 disposed along the cam shaft 530. Each cam lobe 535 may be, for example, circular, oval, elliptical, or other similar shapes. Each cam lobe 535 is offset from a center axis of the cam shaft 530, so that the cam lobe 535 wobbles with respect to the cam shaft 530 when the cam shaft 530 rotates around its axis. Each cam lobe 535 is associated with a movable grate element 520 (FIG. 2B), so the cam lobe 535 is disposed within the cam aperture 570 (FIG. 2B) of a movable grate element 520 (FIG. 2B). The relative orientation of each cam lobe 535 may be adjusted according to the desired horizontal and vertical displacement between adjacent grate elements 520 (FIG. 2B).

The cam lobes 535 may generally be timed differently to prevent all movable elements 520 (FIG. 2B) from moving in the same direction simultaneously. The positioning of the cam lobes 535 may be positioned in a variety of sequences to achieve desired resulting motion for the movable elements 520 (FIG. 2B). Staging the cam timing may provide a consistent movement of both fuel and ash. The cam assembly 590 may be continuously running or started and stopped to achieve the desired results. If bottom combustion air is used properly, so that it passes through the grate elements 510, 520 (FIG. 2B), the grate elements 510, 520 (FIG. 2B) may remain cool enough such that the grate element 510, 520 (FIG. 2B) may be formed from common low cost materials, for example steel or cast iron. Of course, other suitable materials may be used.

The cams 535 may be oriented so the top surface of each of the movable grate elements 520 (FIG. 2B) is raised above the top surface of fixed grate elements 510 (FIG. 2B) while the top surface of each of the movable grate element 520 (FIG. 2B) is moving in a direction corresponding to the desired direction for conveying the ash. Similarly, so the top surface of each of the movable grate element 520 (FIG. 2B) is lowered below the top surface of fixed grate elements 510 (FIG. 2B) while the top surface of each of the movable grate element 520 (FIG. 2B) is moving counter to the direction corresponding to the desired direction for conveying the ash.

A snapshot detail of the end of a second embodiment of a moving grate 500 is shown by FIG. 3. When the cam shaft 530 is rotated, for example, by a motor (not shown), the movable grate element 520 associated with each cam 535 moves in relation to the offset of the cam 535 from the cam shaft 530. The movable grate element 520 is driven to move by the associated cam 535, with the range of motion of the movable grate element 520 restricted by the orientation of the slide aperture 560 of each movable grate element 520. The support rod aperture 527 (FIG. 2B) of the movable grate element 520 may be sized so the movable grate element 520 does not come in contact with the support rod (not shown) as the movable grate element 520 is moved by the associated cam 535.

In the second embodiment, each movable grate element 520 is separated by a fixed grate element 510. As pictured, the rotation of the cam shaft assembly 590 positions a first moving grate element 520A relatively high above the surface plane of the fixed grate elements 510. A second moving grate element 520B is positioned somewhat lower in elevation compared to the first moving grate element 520A. Similarly, a third moving grate element 520C is shown at a position with an elevation below the fixed grate elements 510, and a fourth moving grate element 520D is shown with an elevation essentially coplanar with the fixed grate elements. Similarly, the movable grate elements 520 move laterally back and forth in relation to one another and the fixed grate elements 510. The up and down movement of the movable grate elements 520 helps break up ash and keep ash broken up as it is conveyed, also helping prevent bridging across the entire grate 500. An opening at the end of the firebox 130 (FIG. 1) allows unburned material, for example, ash and clinkers, to pass through the firebox 130 (FIG. 1) and be dropped into an ash receptacle or conveyor (not shown).

The motion of the movable grate elements 520 in relation to one another and the fixed grate elements 510 may assist in breaking up heavy ash and/or clinkers on the surface of the grate 500. In addition, the agitating motion of the movable grate elements 520 may convey items upon the grate surface, for example clinkers and/or solid fuel, in a desired direction.

It should be noted that while the embodiment shown in FIG. 3 has the top surface of each fixed grate element 510 being substantially coplanar, however, there is no objection to other orientations of the fixed grate elements 510. For example, in an alternative embodiment fixed grate elements 510 at the near and far edge of the grate 500 may be raised in relation to the other fixed grates. Such an arrangement may, for example, encourage motion of solid fuel on the grate surface toward the center of the grate from the edges of the grate 500. The top surface of each fixed grate element 510 may be inclined in the desired direction of movement to further induce the movement of solid fuel. However, it should be noted that the agitating motion of the grate 500 may be sufficient to convey solid fuel when horizontally oriented, and even to convey material against an uphill incline.

The motion of a movable grate element 520 is generally periodic, with the period equal to the time for the cam shaft 530 to make a single rotation. A first cam 535 may be oriented differently from a second cam 535, so the motion of an associated first movable grate element 520 is different from the motion of a second movable grate element 520. For example, if the first cam 535 and the second cam 535 are similarly shaped, a curve showing the motion of the first movable grate element 520 would differ from a curve showing the motion of the second movable grate element 520 only by the relative phases. The orientation of adjacent cams 535 may be adjusted to provide for variations in relative movements of adjacent grate elements. Similarly, cams 535 may be of different shapes and sizes to vary the movement cycles of individual grate elements. Note that while the discussion of the periodic movement of cams and grate elements assumes a constant rate of rotation of the cam shaft 530, there is no objection to the cam shaft 530 rotating at an irregular rate, or to sporadically or periodically start and stop rotation of the cam shaft 530.

The motion of the grate elements 520 need not be rapid, only fast enough to break up friable ash of spent solid fuel. The speed the rotating camshaft 530 may be relatively low, for example, on the order of one rotation every 5-10 seconds. However, there is no objection to rotating the camshaft 530 at a higher or lower speed. Similarly, as noted above, the grate elements may not need to be in continuous operation. For example, the grate 500 may generally remain stationary and be periodically activated for short time intervals to remove ash and/or advance fresh fuel to the burner. Indeed, in a system where the grate 500 is used with the gravity feed pellet feeder (described below), it may be preferable that the grate 500 may remain stationary except when a buildup of ash should be removed, as the conveyance of solid fuel by the grate 500 may counteract the desired burn rate characteristics of the gravity feed pellet feeder.

While it is preferable to convey ash from the burner by the agitating motion of the grate 500, once fragmented, the ash may fall through the air passages 550 (FIG. 2B). It may therefore be desirable to taper the air passages 550 (FIG. 2B) to prevent clogging of the air passages 550 (FIG. 2B) with ash such that air flow through the grate 500 is blocked.

In alternative embodiments, the fixed grate elements 510 may have air passages 550 formed in them. The combustion air passageways are recommended to be put into the moving elements, such that they are adjacent and open to the next element. This helps prevent material from plugging the passageways, as the movement can aid in breaking up trapped material.

In further alternative embodiments, all of the grate elements may be movable grate elements 520, with no fixed grate elements 510 used. Movable grate elements 510 may be arranged to alternate with fixed grate elements 520, or adjacent movable grate elements 510 may be used in the grate 500, occasionally interspersed with a fixed grate element 520. Of course, other combinations of fixed and movable grate elements 510, 520 may be used depending on the specific application for the grate 500.

System

A first exemplary embodiment of a solid fuel feeding system 300 is shown in FIG. 4. Under the first embodiment, solid fuel pellets 450 are stored in a hopper 310. The pellets 450 may drop down from the hopper 310 into a pellet feeder 400. The pellets 450 accumulate in a pile on the agitating grate 500, where fuel pellets 450 are consumed by flames 330. As pellets 450 are consumed they are replaced by additional pellets 450 as space becomes available on the grate 500. Agitation of the grate 500 assists in breaking up ash from consumed pellets, whereupon the ash may be conveyed away from the burner 320, for example, into an ash bin (not shown). The pellets 450 may be added to the hopper 310 as needed when the pellet level falls.

A second exemplary embodiment of a pellet feeding system 600 is shown in FIG. 5. Under the second embodiment, fuel pellets 450 are stored in a remote hopper 610. The pellets 450 may be conveyed from the hopper 610 by a mechanized conveyor 620, for example, an auger driven tube, such that pellets 450 may drop down from the conveyor 620 into a pellet feeder 400. The pellets 450 accumulate in a pile on the agitating grate 500. The grate 500 is positioned within a burner 320, where fuel pellets 450 are consumed by flames 330. As pellets 450 are consumed they are replaced by additional pellets 450 as space becomes available on the grate 500. Agitation of the grate 500 assists in breaking up ash 650 from consumed pellets 450, whereupon the ash 650 may be conveyed by the grate 500 into an ash box 660, for example, into an ash bin (not shown). The mechanized conveyor 620 may typically only operate intermittently, for example, feeding pellets until the feeder is filled above a fill line 690, whereupon the mechanized conveyor is dormant until enough pellets 450 are consumed so the top of the pellet pile 450 falls below an add line 680.

Additional embodiments are also possible, for example, where the burner 320 is a downdraft burner, so that flames pass downward through the grate 500. Similarly, the bottom of the pellet feeder 400 may be adjacent to the grate 500, rather than incorporating the grate 500 as the floor of the pellet feeder 400 itself. In other embodiments, a second agitating grate may serve as the mechanized conveyer 620.

It should be noted the number of stationary elements between the moving elements may vary among embodiments, for example, a stationary element may be between all moving elements in some embodiments, while all elements could be moving in another embodiment. Each stationary element may be fixed in space. Each moving element may be fixed on a slide. It may be desirable for gap between adjacent elements to allow for expansion and contraction of the elements, for example, due to heat. The combustion air passing through the elements is generally preheated by the elements which my aid in combustion. Air generally passes through the firebox at a specifically engineered location for the over air, which is commonly used in solid fuel combustion.

Method

FIG. 6 is a flowchart of an exemplary method for conveying pellets. It should be noted that any process descriptions or blocks in flow charts should be understood as representing modules, segments, portions of code, or steps that include one or more instructions for implementing specific logical functions in the process, and alternative implementations are included within the scope of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present invention.

The first exemplary method includes the step of providing a camshaft, as shown by block 710. A step includes providing a movable grate element with a cam end, a slide end, a cam bore disposed substantially at the cam end, and a slide bore disposed substantially at the slide end, as shown by block 720. A cam disposed along the rotating camshaft is provided, the cam disposed within the cam bore in the movable grate element, as shown by block 730. The camshaft is rotated with a camshaft drive, as shown by block 740. The camshaft drive may be a motor, as shown by block 750.

In summary, low power apparatuses for solid fuel feeding and an agitated burner surface have been presented. It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents. 

What is claimed is:
 1. An agitating grate, comprising: a movable grate element comprising: a solid fuel supporting surface; a bottom surface disposed substantially opposite said solid fuel supporting surface; a first side; a second side disposed substantially opposite said first side; a cam end; a slide end disposed substantially opposite said cam end; and a cam bore disposed substantially at said cam end, said cam bore passing through said movable grate element between said first side and said second side; a first rotating camshaft disposed through said cam bore; and a first cam lobe disposed upon said first rotating camshaft, said first cam lobe disposed within said cam bore.
 2. The agitating grate of claim 1, wherein said movable grate element further comprises an air passage.
 3. The agitating grate of claim 2, wherein said air vent further comprises: a first aperture in said movable grate element solid fuel supporting surface; a second aperture in said movable element; and an air channel passing through said movable grate element between said first aperture and said second aperture.
 4. The agitating grate of claim 1, further comprising a stationary grate element adjacent to said movable grate element, wherein said stationary grate element further comprises a solid fuel supporting surface.
 5. The agitating grate of claim 4, wherein said stationary grate element further comprises an air vent.
 6. The agitating grate of claim 5, wherein said air vent further comprises: a first aperture in said stationary grate element solid fuel supporting surface; a second aperture in said stationary element; and an air channel passing through said movable grate element between said first aperture and said second aperture.
 7. The agitating grate of claim 1, further comprising: a movable grate element slide bore disposed substantially at said slide end, said slide bore passing through said movable grate element between said first side and said second side; and a stationary slide pin disposed through said movable grate element slide bore.
 8. The agitating grate of claim 7, further comprising: a second rotating camshaft disposed through said slide bore; and a second cam disposed upon said second rotating camshaft, said second cam disposed within said slide bore.
 9. The agitating grate of claim 1, wherein said solid fuel supporting surface is disposed at an incline angle with respect to a horizontal reference, said incline angle in relation between said cam end and said slide end.
 10. A method for agitating a burner grate, comprising the steps of: providing a camshaft; providing a movable grate element comprising a cam end, a slide end, a cam bore disposed substantially at the cam end, and a slide bore disposed substantially at the slide end; providing a cam disposed along the rotating camshaft, said cam disposed within said cam bore in said movable grate element; and rotating said camshaft with a camshaft drive.
 11. The method of claim 10, wherein rotating is controlled with a motor.
 12. A solid fuel transport system comprising: a solid fuel feeder comprising a chute configured to accommodate a solid fuel pile; and a conveyer configured to receive solid fuel from said solid fuel feeder and convey said solid fuel away from said solid fuel feeder and convey said solid fuel to a destination, wherein said conveyer further comprises: a movable grate element comprising a cam bore; a rotating camshaft disposed through said cam bore; a first cam disposed upon said rotating camshaft, said first cam disposed within said cam bore; and a camshaft drive configured to rotate said rotating camshaft. 